Yarn guiding drum



10, 1967- H. FOSSEN I 3,346,206

YARN GUIDING DRUM Filed Sept. 29, 1965 FIG. 7

United States Patent 2 a 6 Claims. (Cl. 242-431) My invention relates to yarn guiding drums for yarn winding machines or the like. Such yarn guiding drums, as is well known, are subjected at different locations to abrasion of varying degree. A relatively small, though by no means negligible, amount of abrasion occurs .at the surface of the yarn guiding drum due to the fact that the spool lying on or against the surface of the yarn guiding drum has a slip or backlash acting generally opposite to the rotary direction of the yarn guiding drum so that at this location friction occurs which promotes abrasion. Of especially great importance is the abrasion produced by the yarn that is guided in the grooves of the yarn guiding drum. This abrasion is noticeable to a particularly great degree at the reversal points and at the crossover points of the grooves that are formed in the yarn guiding drum. For many years, designers and engineers in this art have, therefore, sought to produce a yarn guiding drum having the least possible abrasion or wear and tear. To accomplish this purpose many difierent appoaches have been undertaken.

The first course that could possibly be taken for achieving a yarn guiding drum having the least possible abrasion is naturally that of constructing the yarn guiding drum out of material which is prone to the least possible abrasion. This approach has the disadvantage, however, in that it cannot be harmonized with the requirement that the yarn guiding drum be as light as possible and as inexpensive as possible, because such tough materials are both heavy and costly. Efforts have therefore been made repeatedly to increase the resistance of the yarn guiding drums to abrasion by merely mounting intermediate layers that are resistant to abrasion at the locations of the yarn guiding drum which are inclined to be subjected more greatly to abrasion. A known expedient has been, for example, fora yarn guiding drum consisting of synthetic material to intersperse within the basic structural material of the drum, during the process of manufacturing the same, a pulverulent component material which is resistant to abrasion. The resistance of the drum to abrasion is thereby achieved; however, a disadvantage arises in that after a lengthy period of use, the component of the yarn guiding drum structural material which is of lower resistance to abrasion is worn away and only the pulverulent material component remains then as a granular surface. A granular surface of this type, however, has disadvan tageous effect on the durability of the guided yarn so that the number of yarn breaks increases.

Other suggestions for producing yarn guiding drums that are resistant to abrasion from a drum structural material which is of limited resistance to abrasion are based on the provision of reinforcements that are resistant to abrasion at the locations of the drum that are particularly strongly subjected to abrasion. Such reinforcements have consisted, for example, of metallic or ceramic pins which are inserted in a more or less radial direction in the structural material of the drum at the crossover and reversal locations of the guiding groove. With regard to protection against abrasion at the groove reversal locations of the yarn guiding drum, this solution was able to provide rather satisfactory results; however, this was not true for protection against abrasion at the groove crossover points of the yarn guiding drum because the insertion of the pins at the crossover points necessitated such a great expendi- ICC ture of work associated with considerable difliculties that it became clear that it would be more advantageous to obtain protection against abrasion at the crossover locations by other means.

Proposals have accordingly been made, for example, to provide bridging members in the form of relatively complex brackets or bows at the crossover locations. Such brackets were placed directly in the peripheral surface of the drum and consequently presented the problem that the yarn would then very easily slide off the drum surface. It appeared more advisable therefore to insert a form member of metal at the crossover location in the plastic drum having a shape corresponding to the entire crossover location. However, it became noticeable after a period of time that the surface of the drum was subject to abrasion due to frictional rotary engagement with the spool lying up against it, and the structural material of the drum at the locations of the grooves adjacent the metal was also subject to abrasion so that the inserted metal members gradually projected out of the drum structural material.

Therefore, a further proposal for protecting the crossover location against wear and abrasion was made wherein a hole was bored at an acute angle to the drum axis into the wall of the groove at the crossover location and a pin having a guide surface overlapping or covering the groove and lying in the mantle or peripheral surface of the drum was inserted in the hole. An essential disadvantage of this pin which served for protecting the drum against wear consisted, however, in that it necessarily had to be located higher than the base of the groove so that the likelihood of retaining the guided yarn at the cross-over location in the flat groove was sharply reduced. As is known to the man of ordinary skill in the art, the yarn guided in the flatter groove portion must pass without guidance over a distance corresponding to the width of the deeper groove portion at the crossover location of the deeper groove. With the last mentioned proposal for protecting against abrasion, due to the fact that the pin is located necessarily higher than the base of the groove, a specific length of the yarn has to be passed freely, i.e., without being guided, directly before or behind the crossover location of the deeper groove, namely until the yarn length reaches the base of the groove again after it leaves the pin lying above the base of the groove. Thus, by employing such means as protection against wear and abrasion there is less assurance that the yarn will be properly guided. Moreover, this protection against Wear has a rather serious disadvantage in that the requirement that the yarn guiding drum be low in price cannot be met because the assembly and the complicated insertion of this means which affords protection against wear considerably increase the cost of manufacturing the drum.

It is accordingly an object of my invention to provide a guiding drum which avoids the disadvantages of the heretofore known yarn guiding drums and which moreover and more specifically has a greater resistance against abrasion than has heretofore been able to be achieved and which more particularly provides good protection against abrasion at the crossover locations of the groove in the drum. It is a further object of my invention to provide such a yarn guiding drum at minimal cost and with minima-l expenditure of labor to produce the same.

With the foregoing and other objects in view, I provide in accordance with my invention a yarn guiding drum having reinforcements located in the structural material of the drum at the crossover locations of the groove that are subjected to great wear and abrasion. The reinforcement consists of a plate-shaped insert resistant to abrasion fixed in the flatter groove portion at its entrance into 7 or junction with the deeper groove portion at the crossover location on the periphery of the drum.

In accordance with other aspects of my invention, I provide at the respective ends of the flatter groove portion, which is intersected and separated by the deeper groove portion, a respective insert resistant to abrasion and having the form of a small plate-shaped disc. The insert is embedded into the structural material of the drum so that the base of the flatter groove portion at the ends thereof located on opposite sides of the intersecting deeper groove portion is formed from the flat upper side of the plate-shaped insert whereby the yarn, even after being used for a lengthy period of time, cannot cut into the basic structural material of the drum.

Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in yarn winding drum, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of a specific embodiment when read in connection with the accompanying drawings in which:

FIG. 1 is an axial view of a portion of a yarn guiding drum constructed in accordance with my invention; and

FIG. 2 is a side elevational view of a portion of the groove wall of the drum shown in FIG. 1, showing the flat end of the insert of my invention.

Referring now to the drawings, there is shown in FIG. 1 a portion of a yarn guiding drum 1 of synthetic material having a conventional yarn guiding groove with a crossover location, wherein the relatively deeper groove portion 2 intersects the relatively flatter groove portion so as to divide the latter into two groove arms 3 and 4. At the ends of the interrupted flatter groove portion respective inserts 5 and 6 of sectoral or semicircular shape are fixedly embedded in the structural material of the drum beneath the flat groove portion arms 3 and 4. Notches or indentations 9 and 19 are provided on the flat sides 7 and 8 of the inserts 5 and 6 respectively which, in the illustrated embodiment, have the form of a semicircular section, these notches 9 and 10 conforming to and providing an extension of the bases 11 and 12 of the respective groove arms 3 and 4. The narrow flat ends 13 and 14 of the respective plate-shaped inserts 5 and 6 which substantially form the respective chords of the semicircular sections are flush with the walls 2 and 2", respectively, of the deeper groove portion.

-By providing the flat side 13, 15 of the respective discshaped inserts 5, 6 with a notch or indentation 9, 10 which conforms to the base 11, 12 of the flatter groove portion, there is afforded not only greater protection against abrasion due to the fact that the rather large tensile force components of the yarn which act in the axial direction of the drum are absorbed in the notches or indentations, but there is also afforded possible further simplification in manufacture. As aforementioned, the known devices for protecting against abrasion require in part a considerable expenditure for the insertion or installation of the means for protecting against abrasion. The insertion of a plate-shaped insert in accordance with the instant invention is, however, especially simple since, for example, by means of a milling tool, a notch or indentation can be milled at the desired location in the Wall of the deeper groove portion conforming to the size of the insert which is to protect the drum material against abrasion, and the insert, for example can then be inserted therein and suitably secured with cement. Since the flat side 7, 8 of the respective plate-shaped insert 5, 6 is provided with a notch or indentation 9, 10 conforming to the respective base 11, 12 of the flatter groove portion, the milling tool need not be adjusted to hundredths of a millimeter but rather, the notch on the plate-shaped insert can be con- 4 formed to the path or course of the flatter groove portion after the insert has been placed in the milled notch. A particularly simple way of producing the protection against abrasion at the crossover location of the grooves formed on the peripheral surface of the yarn guiding drum in accordance with the invention of this application is achieved, as aforementioned, by employing a plateshaped insert having the form of a sector or semicircular section whereby the narrow side of the insert, which substantially forms the chord of the semicircular section, is flush with the wall of the deeper groove or is embedded slightly in the wall. In this case, the recess for the plateshaped insert can be machined relatively simply from the structural material of the drum with the aid of a saucershaped milling tool.

It is known that the yarn at the crossover location of the groove, as the yarn leaves the end of the flatter groove portion 3, for example, is guided fairly accurately in the base 11 of the groove. After crossing over the deeper groove portion and passing into the other end of the flatter groove portion 4 once again, the yarn however often engages a portion of the wall of the flatter groove portion before it runs back onto the base 12 of the groove. An increased abrasion of the groove wall thus takes place at this location. Accordingly, as the yarn continues from the groove wall which is thus engaged thereby and which consists of the relatively soft base structural material of the drum, to the relatively harder insert, a gouged-out ledge injurious to the yarn can form due to the greater abrasion of the structural material of the drum. In order to prevent the formation of such a ledge, in accordance with a further feature of my invention, the plate-shaped insert 6 is located in such a way that the respective flat side 8 of the insert 6 provided with the respective notch or indentation 10 simultaneously forms a portion of the wall surface of the respective flatter groove arm 4 which is engaged by the yarn. Accordingly, the indented edge 15 of the narrow side 14 of the plate-shaped insert 6, for example, advantageously extends over the entire portion of the edge of the groove arm 4 which is engaged by the yarn.

When the yarn crosses from the groove arm 3 to the groove arm 4 of the flatter groove portion, the yarn thus first engages the upper edge 15 of the narrow side 14 of the plate-shaped insert 6 and is displaced thereafter against the notch or indentation 10 and the base 12 of the groove arm 4. Since the flat side of the insert 6 provided with the notch 10 simultaneously forms a portion 8 of the wall surface 4 of the flat groove which is engaged by the yarn, the yarn does not first run onto the drum structural material at this location which is subjected to a great amount of abrasion, but rather directly onto the insert which is resistant to abrasion. As aforementioned, abrasion of the drum structural material at this location is thereby prevented so that no ledge, which Would disturb the normal path of the yarn, can be formed during the passage of the yarn therefrom onto the insert 5.

FIG. 2 shows a fragment of the groove wall 2" as viewed in a direction perpendicular to the flat end surface 14 of the insert 6. It is readily apparent therefrom that the notch or indentation 10 on the flat side 8 conforms to the base of the groove 4, and the upper edge 15 with the portion 8' of the insert 6, which is not visible in FIG. 2, can partly assume the guidance of the yarn.

As mentioned hereinbefore, the insertion or embedding of the plate-shaped insert of semicircular section in the structural material of the drum can take place, for example by milling at a desired location in the walls of the deeper groove a recess corresponding to the size of the plate-shaped insert by means of a saucer-shaped milling tool and cementing the insert in this recess. The plateshaped insert can consequently either be provided with the notch or indentation 9 and 10 before it is cemented into the recess or these notches can be machined therein afterwards. In order to efiect a particularly secure cementing of the insert into the structural material of the drum, it is advantageous to provide the fiat sides of the insert with irregularities, contours, bores or the like (not shown). Moreover, it can be advantageous if both ends of the narrow sides 13 and 14 are so formed that they lie Within the walls 2' and 2" respectively of the deeper groove since danger will then not arise that the edges of the plate-shaped insert will project above the wall of the deeper groove after the abrasion or wearing away of the wall.

It is additionally advantageous if the wall 4' does not gradually slope toward the edge 15 (FIG. 2) or toward the surface 8 (FIG. 1) of the flat side 8 of the insert which is not covered by the wall 4, but rather has the form of a hump 16 so as to avoid the danger of the edge of the structural material of the drum ending in a thin film at its junction with the insert which might consequently lead to loosening or peeling thereof at the crossover location and its projection from the insert.

I claim:

1. In a yarn guiding drum formed with a yarn guiding groove having a relatively flat groove portion intersected by a relatively deep groove portion, the improvement which comprises a plate-shaped insert of material resistant to abrasion by yarn guided in the groove, said insert being embedded in the relatively flat groove portion at the intersection thereof by the relatively deep groove portion so as to form a reinforcement for the drum at said flat groove portion.

2. Yarn guiding drum according to claim 1, wherein said insert has a fiat side formed with a notch conforming to the base contour of the relatively flat groove portion.

3. Yarn guiding drum according to claim 2, wherein said flat side also forms a portion of a wall surface of said relatively fiat groove portion and is adapted to be engaged by the yarn.

4. Yarn guiding drum according to claim 1, wherein said insert has the shape of a sector, said insert having a narrow side forming the chord for said sector and being embedded in a wall of said relatively deep groove portion.

5. Yarn guiding drum according to claim 1, wherein said insert is of substantially semicircular shape.

6. Yarn guiding drum according to claim 1, wherein said insert is sector-shaped and has a narrow side forming the chord of the sector, said narrow side being flush with the wall of said relatively deep groove portion.

References Cited UNITED STATES PATENTS 2,753,126 7/ 195 6 Marcellus 24243 .2 3,022,02 1 2/ 1962 Zollinger 242-43 .2 3,080,135 3/1963 Steijn 24243.2 XR 3,128,957 4/1964 Fallscheer 242-432 STANLEY N. GILREATH, Primary Examiner. 

1. IN A YARN GUIDING DRUM FORMED WITH A YARN GUIDING GROOVE HAVING A RELATIVELY FLAT GROOVE PORTION INTERSECTED BY A RELATIVELY DEEP GROOVE PORTION, THE IMPROVEMENT WHICH COMPRISES A PLATE-SHAPED INSERT OF MATERIAL RESISTANT TO ABRASION BY YARN GUIDED IN THE GROOVE, SAID INSERT BEING EMBEDDED IN THE RELATIVELY FLAT GROOVE PORTION AT THE INTERSECTION THEREOF BY THE RELATIVELY DEEP GROOVE PORTION SO AS TO FORM A REINFORCEMENT FOR THE DRUM AT SAID FLAT GROOVE PORTION. 